一种宽频带高稳定相位中心导航天线的设计

设计了一款基于阿基米德螺旋天线的宽频带高稳定相位中心导航天线.采用阿基米德螺旋天线结构实现了宽带驻波带宽和轴比带宽，结合三维扼流环结构改善了天线相位稳定度和多径抑制能力.通过有限元电磁仿真软件建立了仿真模型和完成了参数优化设计，所设计的宽带高稳定相位中心导航天线的指标达到:在GPS、北斗、GLONASS和Galileo卫星导航系统的所有工作频点上，输入端口驻波比均小于1.45；在俯仰角-60°~60°主波束范围内轴比小于3 dB，相位稳定度在-2.5°~2.5°，方向图增益均在5 dB以上.相比于未加载扼流环，所设计天线的增益前后比改善2~6 dB（仰角60°和仰角120°对应增益差值）.该研究表明，结合了三维扼流环结构的阿基米德螺旋天线综合性能优异，适于设计宽频带高稳定相位中心天线.

Design of a broadband and high stable phase center navigation antenna

A broadband and high stable phase center navigation antenna is presented,in which wide voltage standing wave ratio (VSWR) and axial ratio (AR) bandwidths are realized by adopting Archimedes spiral antenna structure.Both phase center stability and multipath-suppressing capability are improved by designing a proper three-dimension(3D) choke-ring surrounding the Archimedes antenna.Correspondingly,a simulation model of the proposed antenna is established with a kind of commercial electromagnetic simulation software and its parameters are optimized simultaneously.The simulation results demonstrate that at all the operation frequency points of the GPS,COMPASS,GLONASS,and Galileo satellite navigation systems the VSWR is less than 1.45,AR less than 3dB in the main beam of elevation from-60°to 60°,phase center stability from-2.5°to 2.5°in the same main beam,and the gains of the frequency points are more than 5dB,etc.In contrast to the pure Archimedes spiral antenna,the front/back gain ratio (FBR) (defined as the difference of the gain values at elevation 60°and elevation 120°) of the loaded 3D choke-ring Archimedes antenna is improved as 2-6 dB.The work shows that the proposed antenna has a distinct advantage.